The present invention relates to a hydraulically actuatable directional control valve, particularly a directional proportional control valve, which is to be controlled by electromagnetically actuated pilot valves of small nominal sizes.
In connection with these valves, it is known to fasten the pilot valves of small nominal size having a housing of their own to the lateral end surfaces of the housing of the directional control valve and to establish the hydraulic connection and of these pilot valves with the tank and pressure connection with the directional control valve via bored channels in the housing of the directional control valve. Since the connection pattern of the known pilot valves of small nominal size has results in connecting channels of small diameter at a slight distance from each other, the introduction of these connecting channels in the form of bore holes requires a considerable manufacturing expense. Instead of pilot valves which are fastened to the side of the housing of the directional control valve, it is also known to develop the pilot valves as insertion cartridges and screw them into the housing of the directional control valve parallel to the actuation axis of the servo-piston of the directional control valve and to connect the pilot valves hydraulically to the directional control valve by separate bore holes in the housing of the directional control valve. Such a development and arrangement of the pilot valves in the housing of the directional control valve requires expensive production of the connecting bore holes, particularly as they must close in pressure-tight fashion, without leakage towards the outside.